When constructing concrete structure, it is common practice to use formwork in which steel reinforcement is placed, assembled and inter-tied in situ, prior to concreting. Such in situ placed and assembled reinforcement commonly requires a large number of manhours. The reinforcement is made from straight bars, pre-bent bars and stirrups which are tied together in the formwork prior to concreting. In many instances, the bars are pre-cut and bent and to an extent handled by cranes. Such bars may have a length of for example 20 m and a diameter in the range of for example 10 mm-50 mm, each bar thus representing a large weight and being heavy to handle for the operators placing the reinforcement.
Further, it is common practice to prefabricate steel reinforcement cages in a sheltered store and then transport the preassembled cage on trucks to the construction site for placement in the formwork, thereby reducing the time spent on site for handling and placing, such operations being performed by means of lifting cranes.
Recently it has also been proposed to make the reinforcement of carbon or basalt fibers, embedded in a resin matrix. Reference is made to the applicants own U.S. Pat. No. 7,396,496, the content of which hereby being incorporated by the reference with respect to the prefabrication of reinforcement structure for a concrete pillar. According to U.S. Pat. No. 7,396,496 reinforcement is made of carbon or basalt fibers, forming bars, spirals or reinforcement nets.
US 2008/0263989, also belonging to the applicant, disclose reinforcement comprising at least one or more loops with closed ends, forming end anchorage for the reinforcement US 2008/0263989 is hereby incorporated by the reference.
There is a need for a reinforcement system which is easy to handle without having to depend on heavy use of cranes for lifting heavy reinforcement units or bars and which still is flexible in use and easy to adapt to the various concrete structured and shapes to be concreted. Further, there is a requirement for a system requiring a minimum of manhours to produce a complete, reinforced structure, ready for concreting. A still further requirement is to arrive at a reinforcement system where the need for concrete coverage is reduced to a minimum without putting the concrete structure at a risk for failure due to corrosion or the like.